Thread: 700R4 "Lock up" Torque converter

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Well, I think I have given up on finding an affordable T56 (or any other standard overdrive tranny) to put behind my stock 454, in my Bel Air. As much as I wanted to manually shift, I don't think its going to happen. I am now looking at a 700R4. I really want an overdirve to take the family on those long trips.

Anyone have experience with this tranny? What did you use for a torque converter? I d like to use an aftermarket one with a higher stall speed. How about a "lock up" switch, what did you use?

Surpsingly, I don't see too many aftermarket "lock up" torque converters out there (Summit only lists one). Any feedbakc would be great, thx guys

You definitely need the lockup. On long trips in overdrive, the trans will overheat and convert itself into a boat anchor. The other critical adjustment is in the TV cable.

http:\\www.bowtieoverdrives.com

A little wiring in the trans, and a switch in the brake line, and you've got it. You can also add a manual switch to lock it up in any gear.

Call them for an application. They also have some interesting reading on the site.

Well it took me almost a year to get mine all set up and working But I am a slow old guy.

I have the 700 behind a BBC. There is no more need for switches. There is now a hyd lock up for 4th gear thats in the valve body. Cost about 150 extra depending on who you get the tranny from. It can also be setup to lockup at the MPH (or close) to what you want. I wanted mine as low as it would go. It locks up about 38 MPH and I love it compared to the th400. I can now pass a gas station.

Search around. I can't really recomend a trans shop because I had almost a years worth of trouble. I also have a lock up spare valve body because they thought that was the problem why mine wouldn't lock up. Turned out to be the governor. The valve body is for sale 150 + shipping because that's what it cost me to have it replaced. I know it works because it would lock up and then unlock off and on. The governor was the problem. There were burrs on the outter flapper that the inner flapper got stuck on. Of course you don't know this in the car. In hand I found the problem. Actually a file could have fixed it but they sent me a new one so I used it.

I am very satisfied with the 700. Don't know about the strip. Broke the first one on the 3rd run. Second one has held up with about 20 runs. Well see.

I am running a 3600 flash stall, 3200 on foot brake. Works excellent on the street. Proly could use a little more for the strip.

Jud

Give these guys a call, they have a hydraulic lockup version.

http://www.eatmyshift.com/

Don Shillady
Retired Scientist/teen rodder

I build 700s for street rods I use one wire lock-ups kevlar band up to 2600 stall converter accurate speedo gearing to your tire size and rear end ratio I build different stages dedpending on your motor The one i would recomend to you I have put behind big bolcks with blowers. I get $1100 and will take off $100 if you supply the core. I am in Middleton ma. I do not ship but I will install. I sell at Lake componce , Thomson and Amherst Nh Swap Meets. You can Email Me at astreetrodtrans@aol.com I will answer any Questions you have.

we are a dealer for Monster trans. They will set up the trans to work with your cars specs.Motor specs ,tire size and rear gear ratio so the speedo reads correct.the lock up convertor works off the brake light switch. a 1 wire hook up.we offer a 5% discount and the shipping is FREE.
Tim

Paradise,

My setup is just sitting in the garage waiting for installation of the radiator and electrical stuff so I have not run my Monster 700R4 yet but I got the one with the hydraulic lockup. You say you resell the MM units but then mention a one-wire lockup. Can you compare the electrical lockup with the hydraulic lockup version? With the electrical lockup it seems to me that you have to hit the brakes to get a downshift? I liked the idea of the hydraulic lockup so that if I encounter a steep hill in OD I should get an automatic downshift?

Don Shillady
Retired Scientist/teen rodder

I was looking at the lock up kit from Painless Wiring. They seem to make some quality products and I would trust them (I think...)

I am also leery about hooking my tranny up to something as flimsy as a brake light switch. From what I have been reading, I understand that if you do not lock these things up correctly, you can overheat and ruin them quickly...

Ok guys I think there is a little confusion as to how od trans works.Don your trans is the same as what we sell from monster. The shift points are controlled by the valve body in the trans. so the trans will shift automatic up or down. You would not have to hit the brake to shift down.
GM ran there's off the brake light switch to supply power to the trans to the convertor lock up automatic in third gear and 45mph. the brake light was used to unlock or break the circuit so
the convertor would unlock at a stop. if it did not the trans would try and push the car through the light.
Monster on the other hand has corrector the problem that was the death of many 700Rs with using a toggle switch to provide power to the trans with the option of unlocking the converted manually. To tow or drag race the car. Monster also fixed the 3rd gear lock up to 4th only.This was a problem for GM. there cars would surge when the car was at 45 because the trans would lock and unlock the convertor in third gear.
Hope this helps Tim

Gus,

The brake light switch doesn't lock the converter - it unlocks it when you put on the brakes. That way, you don't stall the engine if you lock up the rear wheels while in OD.

I like the electrical version becaue the addition of a toggle switch allows you to lock the converter in 2nd or 3rd gear. That way, if you're doing a lot of low RPM driving in one of those gears, you can lock it up and eliminate almost all heat generation. This is a definite advantage if you're driving at an rpm lower than your stall speed.

Don,

I believe that the downshift is controlled by the TV cable. I don't think you'd have to hit the brakes in order to downshift. The alternative is to pull the gearshift handle back from OD to D. The converter would unlock automatically, since the lockup is only in OD (assuming you don't have the additional switch wired in and turned on.)

I understand that the brake light disengages the lock up (not downshifts it). Interesting thought about "driving at an rpm lower than your stall speed" though... I was thinking of using a 2800 - 3000 or so converter, I need to calculate my target RPM range when cruising at about 70 mph on the hiway...

Are you guys saying that the electrical lock up switch is completely manual? I would have to lock and unlock the TC myself, sounds like a pain. This is why I was leaning toward the hydraulically (sp?) controlled unit.

My 4 speed OD auto truck gets into OD just on everyday backroad driving, not just on the hiway, if I had to reach over and turn it on and off as I cruised down every long stretch of farm road I'd get a cramp as well as annoyed.

Thanks guys, I'm learning. Paradise, I am running with a 3.55 rear gear and a 1400 rpm stall converter but with the OD I may be running around 1650 rpm or so (tall tires) so if I have to adjust the shift points will that be easy to do on the outside of the trans or is that set within the throttle body? Henry seems to indicate this may be within the range of the TV cable. Sorry to talk this to death but I am a little concerned about setting up the TV cable myself without some feeling for where the shift points are. I guess the real answer will be to take the car to a transmission shop and let them have fun setting the TV cable while they get free rides in my car. Just for further confirmation, I had a 2.73 rear when I ordered the trans and got the speedo gears for a 2.73, then I switched to a 3.55 rear gear and never installed the different gears in the trans. I am hoping/assuming by installing a magnetic pickup the little computer in my electronic speedometer can adjust for the wrong speedo gear in the trans. Actually I have the correct speedo gear for the 3.55 rear so I guess the right thing to do is just do a littl undercar work and put in those gears. Just taking advantage of the kowledge available on this Forum, thanks!

Don Shillady
Retired Scientist/teen rodder

Are you guys saying that the electrical lock up switch is completely manual? I would have to lock and unlock the TC myself, sounds like a pain. This is why I was leaning toward the hydraulically (sp?) controlled unit.

Nope, that's not what I'm saying. The switch is optional, and only necessary if you want to lock up the converter in 2nd or 3rd gear. When you put on the brake, the converter unlocks.

Don,

I don't know how to answer your question. I've studied how my setup will work, and never considered a hydraulic converter. I have the electronic controlled version in my Vette (stock), so I stuck with what I knew. The 700R4 in my Vette is not really a computer controlled transmission. It's a standard automatic with an electrical lockup. The pure computer controlled version is the 4L60E. The R4 in my Vette has 120K miles on it, and it still works fine.

Oh, and the electric speedometer I have doesn't care much about gears. There's a calibration sequence that you set while driving.

ok first of all a 700r4 uses 2nd gear oil to lock-up the converter you can run power and ground to the tcc solonoid and it will not lock-up the converter at as stop because you don't have 2nd gear passages pressuresized no need for brake switch . I use the 4th gear switch which comes in the trans to lock-up the converter. one wire no kit no brake switch no toggle switch to forget and smoke the trans there is a reason you call it an atomatic.200r4 125 3254l and 350c trans can lock up the converter in 1st not a 700r4 Next stall speed has nothing to do with cruseing down the hiway a 70 the converter is locked up no slip at all.

yup, stall speed is only an issue with a non lockup converter. got it

Nope, that's not what I'm saying. The switch is optional, and only necessary if you want to lock up the converter in 2nd or 3rd gear. When you put on the brake, the converter unlocks.

Henry, Now I am getting confused about a trans I thought I understood...

Your saying that if I did nothing to the 700R4 other than install it, the torque converter would lock itself at a point in 4th gear? I thought the reason all of us were monkeying with either an eletrical switch or this hydraulic kit is the lack of a cpu on board to control TC lock up.

I was under the assumption that due to the lack of a cpu, a hot rodder had to manaully control TC lock up with either an eletrical switch kit OR install the hydraulically controlled switch (so the TC locked up in more of an "automatic" fashion)